Chemistry of Materials · 1997 · 102 citations · 5 references
Natural SciencesChemistryMaterials ScienceCrystal StructureMaterials ChemistrySolid-state ChemistryCrystal ChemistryCrystal SystemsCrystallographyInorganic MaterialsX-ray DiffractionAb Initio CalculationsAb Initio Structure SolutionPorous Silica MaterialsPowder DiffractionPowder X-ray DiffractionSilica-based MaterialsSilicate Crystal StructuresSynchrotron Diffraction
The new pure silica polymorph ITQ-4, structure code IFR, Si32O64, monoclinic I2/m a = 18.65243(13), b = 13.49597(8), c = 7.63109(6) Å, β = 101.9781(5)°, is a zeolitic material containing a large sinusoidal channel with 12-member ring windows as minimum apertures. Its void volume (0.21 cm3/g) is surpassed only by that of pure silica Beta among the known pure silica polymorphs. The success of the ab initio structure solution from synchrotron powder diffraction data was greatly assisted by the absence of Al and Si−OH defect groups, which generates a very high degree of crystallographic order.
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